Liquid pick-up unit and method for a pavement grooving machine

ABSTRACT

A liquid pick-up unit intended to pick up water or other liquid used to cool and flush the grooving head of a pavement grooving machine. An enclosure connected to the grooving machine encloses the grooving head which projects downwardly to engage the pavement through an opening in the lower part of the enclosure. A seal connected with the enclosure, projecting into sliding relation with the pavement, extends in spaced peripheral relation about the grooving head to substantially prevent escape of the liquid. Vacuum is applied to the interior of the enclosure to assist the seal in preventing the escape of liquid from the enclosure. An outlet in the enclosure is positioned to receive liquid and abraded pavement material (swarf) flung centrifugally from the outwardly moving side of the grooving head. The mixed liquid and swarf is delivered to a settling tank in a tank or vehicle towed by the pavement grooving machine. The separated liquid is then recirculated back against the grooving head.

United States Patent [191 Miller [451 Dec. 2, 1975 LIQUID PICK-UP UNIT AND METHOD FOR A PAVEMENT GROOVING MACHINE [75] Inventor: Harold C. Miller, Chicago, Ill.

[73] Assignee: Engelhard Minerals & Chemicals Corporation, Murray Hill, NJ.

22 Filed: Aug. 16, 1974 21 Appl. No; 498,234

Primary ExaminerFrank L. Abbott Assistant E.\'aminerWilliam F. Pate, III

1 1 ABSTRACT A liquid pick-up unit intended to pick up water or other liquid used to cool and flush the grooving head of a pavement grooving machine. An enclosure connected to the grooving machine encloses the grooving head which projects downwardly to engage the pavement through an opening in the lower part of the enclosure. A seal connected with the enclosure, projecting into sliding relation with the pavement, extends in spaced peripheral relation about the grooving head to substantially prevent escape of the liquid. Vacuum is applied to the interior of the enclosure to assist the seal in preventing the escape of liquid from the enclosure. An outlet in the enclosure is positioned to receive liquid and abraded pavement material (swarf) flung centrifugally from the outwardly moving side of the grooving head. The mixed liquid and swarf is delivered to a settling tank in a tank or vehicle towed by the pavement grooving machine. The separated liquid is then recirculated back against the grooving head.

12 Claims, 7 Drawing Figures US. Patent Dec. 2, 1975 Sheet 1 of2 3,923,341

Sheet 2 of 2 3,923,341

US. Patent Dec. 2, 1975 Mir /0 c VACUUM LIQUID PICK-UP UNIT AND METHOD FOR A PAVEMENT GROOVING MACHINE BACKGROUND OF THE INVENTION This invention relates to a liquid pick-up unit and method, for picking up, clarifying and recirculating the liquid used to cool the grooving head of a pavement grooving machine.

To improve the traction of vehicle wheels on rainsoaked pavements, such as roads and aircraft runways, it is known to cut shallow, parallel grooves in the pavement to promote escape of water between the pavement surface and the vehicle wheels traveling thereon. Grooving of the pavement is commonly performed by specialized pavement grooving machines which typically include at least one rotary grooving head. The grooving head comprising a plurality of spaced, parallel, abrasive rotary cutters discs mounted on a common shaft, which engage the pavement to cut grooves therein as the pavement grooving machine moves along it. To prevent the cutters overheating and to flush away abraded pavement material, water is sprayed onto the blades as they rotate downwardly into cutting engagement with the pavement. The water is commonly supplied from tanker vehicles which must periodically be changed over as the water supply is used up or becomes polluted with pavement material.

From time to time, attempts have been made to develop systems in which the water sprayed against the grooving head is picked up, subjected to clarification and recirculated against the grooving head, thereby prolonging the use of the water supply effected by any single tanker vehicle.

One such prior system mounts the grooving head within an enclosure having a peripheral flexible skirt engaging the pavement to reduce the escape of water. Positioned within the enclosure extending peripherally around the interior of the seal are a large number of closely spaced, vertical suction nozzles extending downwardly to pick up the spent water and pass it to a towed tanker vehicle containing a settling tank. The settled out liquid is then recirculated against the grooving head.

Although believed to be generally satisfactory for its intended purpose, certain problems may occur in the operation of such prior system. One problem is that it may be difficult to distribute suction evenly over such a large number of suction nozzles, particularly if some of the nozzles become wholly or partially clogged with abraded pavement material during operation. Thus, there may be local regions of weak suction in which water may pool in those regions and leak out under the seal, thereby causing loss of water and spreading spent water and abraded pavement material over the road surface which must be cleaned off. A further problem arising from the use of vertical suction nozzles is that although they provide plenty of suction close to the pavement surface, there may be a substantial quantity of foam produced (comprising swarf, liquid and air bubbles) which accumulates in the upper region of the enclosure above the grooving heads and is substantially unaffected by the suction nozzles. Should such foam build-up occur, when operation is temporarily stopped, for example, to change over the water vehicles, then the foam and other materials may commence to leak downwardly, depositing a large amount of dirty water and entrained material on the road surface, some of which may leak under the skirt and require to be cleaned away.

Another approach to picking up the spent water and abraded pavement material is to position a collecting chamber within the enclosure in a location to receive the liquid being thrown off the upwardly traveling side of the grooving head, such as the system shown in US. Pat. No. 3,572,841 to Harry W. Rhodes. Although such a system is believed to be generally satisfactory, the absence of positive suction pick-up may, on occasion, leave significant quantities of water on the pavement surface. In addition, the problem of foam build-up in the upper part of the enclosure is still unresolved and can present problems of leak-down when the equipment is stopped.

SUMMARY OF THE INVENTION A liquid pick-up unit according to the present invention provides an enclosure surrounding the pavement grooving head and a resilient peripheral seal extending between the enclosure and the pavement surface to confine liquid within the enclosure. To assist the seal in preventing passage of liquid outwardly of the enclosure between the seal and the pavement, vacuum is applied to the upper part of the enclosure, thereby tending to assist the seal in preventing outward passage of liquid. The vacuum is applied at a location well above the pavement surface so that the possibility of clogging due to abrasive material entering the vacuum system is avoided, thereby avoiding the creation of regions of weak vacuum adjacent certain areas of the flexible seal which could otherwise permit liquid to leak outwardly in those regions.

Instead of picking up the liquid and abraded pavement materials through narrow bore suction nozzles which may become clogged, the liquid pick-up unit of the invention provides a transverse collecting chamber positioned to receive the liquid and abraded pavement material flung off the upwardly traveling side of the grooving head. Liquid is withdrawn from the collecting chamber by a conduit connected to a suitable pump.

The application of suction to the upper part of the enclosure avoids foam build-up above the grooving head as any such foam is drawn out through the suction port in the enclosure. Any foam thus drawn off is delivered to an air separator unit where the liquid is separated from the air and delivered to the stream of liquid withdrawn directly from the collecting chamber by the pump. The combined liquid streams pass to a settling tank in a tanker vehicle towed by the pavement grooving machine. After settling, the separated liquid is recirculated against the grooving head.

With the construction described, the liquid is efficiently picked up from the pavement surface without substantial opportunity for the liquid pick-up unit to become clogged by abraded paving material. Further, the vacuum maintained within the enclosure materially assists the seal in substantially preventing escape of the liquid from the enclosure between the seal and the pavement surface. In addition, the application of vacuum to the upper part of the enclosure avoids the possibility of build-up of foam within the upper part of the enclosure, which might subsequently leak down and pool on the road surface when the equipment is temporarily stopped.

The foregoing and other advantages are more fully described in the detailed description which follows:

BRIEF DESCRIPTION OF THE DRAWINGS A liquid pick-up unit, constructed in accordance with the preferred embodiment of the invention, is illustrated in the accompanying drawings in which:

FIG. 1 is a side view of a pavement grooving machine and tanker vehicle incorporating a liquid pick-up unit according to the preferred embodiment of the invention;

FIG. 2 is a diagrammatic view of the liquid pick-up unit utilized with the pavement grooving machine and tanker vehicle shown in FIG. 1;

FIG. 3 is a cross-sectional plan view of a portion of an air separator unit forming a part of the liquid pickup unit shown in FIG. 2 taken along the lines of3-3 therein;

FIG. 4 is a front view, partially in cross-section, of a grooving head enclosed within an enclosure forming a part of the liquid pick-up unit shown in FIG. 2;

FIG. 5 is a cross-sectional front view of the enclosure shown in FIG. 4 with the grooving head removed;

FIG. 6 is a fragmentary view on an enlarged scale of a portion of the alternative embodiment of the enclosure shown in FIG. 5; and

FIG. 7 is an enlarged cross-sectional view of a portion of the alternative embodiment of the enclosure, shown in FIG. 6.

DETAILED DESCRIPTION Referring to FIG. 1, a pavement grooving machine equipped with a liquid pick-up unit constructed according to the preferred embodiment of the invention including an attached water tanker vehicle, is there shown.

The pavement grooving machine includes a truck 10 pulling a yoke-like trailer vehicle 12 which carries a module 14. The module 14 includes a horizontal base 16 having a plurality of grooving heads 18 mounted beneath it. A motor 20 for driving the grooving heads is mounted on the upper surface of the base 16. The grooving heads 18 each comprise a driven shaft 22 (FIG. 2 and 4), extending transversely of the direction of motion of the grooving machine, and a plurality of abrasive rotary cutters 24 mounted on the shaft in spaced parallel relation, which engage the surface of the pavement over which the machine is traveling to cut grooves in it. The structure and operation of the grooving machine and grooving heads thus far described is fully disclosed in the copending patent applications of Stafford M. Ellis for a Pavement Grooving Machine, U.S. Pat. Ser. No. 261,360 filed June 9, 1972; for a Pavement Grooving Machine Including a Cutting Blade Guidance System, U.S. Pat. Ser. No. 476,461, filed June 5, 1974; and for a Pavement Grooving Machine Having Plural Independently Movable Grooving Heads, U.S. Pat. Ser. No. 476,462 filed June 5, 1974. The pertinent disclosures of each of the aforementioned patent applications of Stafford M. Ellis, which are assigned to the same assignee as the assignee of the present application, are incorporated herein by reference.

In the operation of the grooving machine, it is necessary to spray water onto the grooving heads to cool the cutters so that they do not overheat and become damaged and to flush away the abraded pavement material. In the apparatus of the present invention, the water is supplied by a wheeled tanker vehicle 26 (FIG. 1). The

tanker vehicle'26 can be driven along the roads under its own engine power to deliver water between the site of grooving operations and a remote water supply. During grooving the vehicle 26 is connected at its front end to the rear end of the trailer vehicle 12 by a conventional vehicle hitch 27, and is towed behind the grooving machine. Conventional releasable pipe couplings are also provided to enable the tanker to be releasably connected to the various liquid conduits hereinafter described. Water is supplied from the tanker vehicle 26 to the cutting heads and is thereafter picked up by the liquid pick-up unit of the present invention, returned to the tanker vehicle 26 and subsequently recirculated back to the grooving heads 18.

Each grooving head 18 (FIG. 4), as previously described, includes the rotary abrasive cutters 24 mounted in spaced parallel relation on the rotary shaft 22. A drive pulley 28 mounted on the inner end of the drive shaft 22 rotates the cutting blades 24 to abrade the underlying pavement and thereby cut spaced parallel grooves in it. The shaft 22 is journaled adjacent its opposite ends in vertical, spaced, opposed inner and outer end walls 29 and 30 respectively. A horizontal, curved upper wall 34 extending transversely in spaced, concentric relation around the upper part of the grooving head 18 extends between and is connected to the end walls 28 and 30. It will be understood that the upper wall 34 and the end walls 28 and 30 collectively define an enclosure enclosing the grooving head and having a downwardly facing opening through which the grooving cutters project into engagement with the pavement. Lifting and supporting mechanism generally designated 36, which is disclosed in the previously referred to application of Stafford M. Ellis for a Pavement Grooving Machine Having Plural Independently Movable Grooving Heads, connects the enclosure and the grooving head 18 supported thereby to the remainder of the pavement grooving machine.

The forward end of the upper wall 34 in the direction of travel of the grooving machine (FIG. 2) terminates generally on a vertical level with the center line of the shaft 22 carrying the grooving cutters. Secured to the lower forward end of the upper wall 34 is a forwardly and downwardly slanted front wall 38 connected at its opposite transverse ends to the inner and outer end walls 29 and 30. The front wall 38 has an integral L- shaped flange 40 at its forward extremity. Spaced behind, and parallel to, the L-shaped flange 40 is a horizontal bar 42 also connected to the end walls 29 and 30. The L-shaped flange 40 and the bar 42 support two downwardly and rearwardly inclined, transversely extending, front seals 46. The front seals 46 are made from a resilient flexible elastomer such as rubber, and slidably and sealingly engage the pavement as they travel over it.

The rearward end of the upper wall 34 in the direction of travel of the grooving machine terminates above the center line of the shaft 22. Fixedly connected to the rear side of the upper wall 34 extending transversely in generally parallel relation to the grooving head is a boxshaped housing 50. The housing 50 includes a horizontal upper wall 52 secured at its forward end to the upper wall 34 of the enclosure extending rearwardly therefrom, a vertical wall 54 depending from the upper wall 52 to a point on a level generally level with the members 42 and 40, and a horizontal, forwardly extending, lower wall 56. The lower wall 56 supports three transversely extending, flexible rear seals 58 which extend downwardly into sliding sealing relation with the pavement and are of generally similar construction to the front seals 46.

Extending along the lower ends of the end walls 29 and 30 are two U-shaped flexible end seals 60 (FIG. 4) which also slidably and sealingly engage the pavement. It will be appreciated that the end seals 60, together with the front seals 46 and the rear seals 58, collectively define a peripheral seal extending in surrounding, spaced relation around the grooving head to substantially prevent escape of liquid from within the enclosure.

Liquid is introduced to the enclosure by a transversely extending liquid supply member 62 (FIGS. 2 and 4). In the preferred embodiment, the liquid supply member 62 is a water spray tube having a plurality of openings along its length, each partially receiving an adjacent peripheral portion of one of the rotary cutters 24 to deliver water thereto, as is more fully disclosed in applicants copending application, US. Pat. Ser. No. 369,936, filed June 14, 1973, entitled Water Applicator For A Pavement Grooving Machine. Alternatively, it would be possible to utilize a water spray tube equipped with a plurality of nozzles, spaced from and facing toward the grooving cutters. Water is supplied to the liquid supply member 62 through a conduit 64 (FIG. 2) supplied with water from the tanker vehicle 26 via an intervening water pump (not shown).

As shown in FIG. 2, the grooving head 18 is operating in a down-cutting mode in which the forward side of the grooving cutters in the direction of travel are moving downwardly into the pavement. Water supplied by the supply member 62 is flung off the rearward, upwardly traveling side of the rotary cutters 24, together with swarf abraded from the pavement by the cutters, by centrifugal action. The liquid and swarf flung off the rearward side of the cutters is received by a collecting chamber 66. The collecting chamber 66 is defined by the lower wall 56 of the housing 50, a portion of the rear wall 54 and an interior wall 68. The interior wall 68 is secured at its rear, upper extremity to the rear wall 54 and includes a forward portion 70 secured, adjacent its forward end, to the forward end of the lower wall 56. The forward portion 70 extends in parallel spaced tangential relation to the adjacent portion of the cutters and blends into an arcuate curve at its upper end. A transverse slot 72 extending lengthwise of the inner wall 68 parallel to the grooving head constitutes an outlet through which the liquid and swarf is flung outwardly of the enclosure into the collecting chamber 66.

The mixed liquid and swarf entering the collecting chamber 66 is withdrawn from it through a pipe 76 connected at its remote end to a pump 78. The pipe 76 is of sufficiently wide bore to substantially eliminate any possibility that it might become clogged by the swarf abraded from the pavement.

The pump 78 is a rubber-lined Moyno pump capable of pumping the liquid and entrained abraded pavement particles without damage to itself. In the preferred embodiment, a power source 80 for the Moyno pump 78 is interlocked in its operation with the pump (not shown) for pumping water from the tanker vehicle 26 to the liquid supply member 62. Thus, whenever water is being pumped to the liquid supply member 62, the pump 78 is also operating to withdraw liquid from the collecting chamber 66. The downstream side of the pump 78 is connected to a. main conduit 82 which extends rearwardly to the tanker vehicle 26.

The tanker vehicle 26 is divided internally into a plurality of settling tanks of the type disclosed in FIG. of US. Pat. No. 3,598,446 to Cecil W. Hatcher, assigned to the same assignee as the present application. Insofar as the Hatcher 446 patent discloses settling tank structure pertinent to the tanker vehicle 26 of the present invention, the disclosure of the Hatcher patent is incorporated herein by reference. The liquid leaving the final one of the settling tanks in the tanker vehicle is substantially clarified and free of swarf and is recirculated back to the liquid supply member 62.

The action of the seals 46, 58 and 60 in retaining the water within the enclosure is assisted by applying vacuum to the interior of the enclosure. The vacuum is applied by a vacuum pump 84 (FIG. 2) via an interposed separator unit 86 (to be described) to a conduit 88 connected to the upper wall 52 of the housing 50. The interior of the housing 50 above the inner wall 68 constitutes a second chamber 90 to which vacuum is applied through the conduit 88. The end of the upper enclosure 34 terminates above the inner wall 68 to define a second transverse slot 92, spaced above the opening 72. The slot 92 constitutes a suction port placing the vacuum chamber 90 in communication with the interior of the enclosure so that vacuum is applied to the entire interior of the enclosure.

The vacuum thus applied has a double effect in assisting the seals in preventing passage of water out of the enclosure beneath the seals to the pavement. By acting directly on the liquid on the pavement within the enclosure, it exerts a pressure gradient which is in an inward direction relative to the enclosure tending to resist flow of the liquid outward of the enclosure. Further, by acting on the interior vertical surfaces of the rear seals 58 and end seals 60 it tends to rotate those sides towards.

the interior thereby urging those seals more firmly against the pavement and increasing their sealing effect. The vacuum pump 84 continues to run, even when the Moyno pump '78 and the pump supplying liquid to the liquid supply member 62 are both shut off (for example, during periods of tanker vehicle changeover) in order to hold the liquid within the enclosure and prevent seepage beneath the seals.

The vacuum applied also tends to withdraw through the conduit 88 any foam, and liquid in the upper part of the enclosure which would not be removed by suction sources acting at pavement level. Thus, the problem of build-up of foam in the upper part of the enclosure with subsequent leak-down when the equipment is shut off, leading to puddling on the pavement, is avoided.

It is the function of the separator unit 86 to separate the liquid constituent of the mixed air and liquid withdrawn through the conduit 88. The separator unit 86 comprises a closed, rectangular, vertical chamber 94, mounted on the base 16, having a vacuum connection 96 adjacent its upper end connected to the vacuum pump 84. The level of vacuum in the air separator unit may be adjusted by a conventional air bleed valve 97 mounted in the side of the chamber 94. Also adjacent the upper end of the chamber 94, but vertically below the vacuum connection is an inlet 98 which communicates, via the conduit 88, with the suction port 92 through which liquid mixed with air is drawn out of the enclosure. The inlet 98 is a downwardly facing elbow pipe directing incoming mixed liquid and air downwardly within the chamber 94. When utilizing a pavement grooving machine having plural heads, such as that disclosed in the aforementioned patent applications of Stafford M. Ellis, four of the inlets 98 are provided. The inlets 98 are disposed in pairs entering through the opposed side walls of the chamber 94 (FIG. 3) with each of the inlets being connected to a different one of the four grooving heads.

Extending slantwise across the interior of the chamber 94, interposed between the inlets 98 and the vacuum connection 96, is a foraminate, liquid-impervious baffle 100 which permits the air to pass through to the vacuum pump 84 but prevents the passage of the liquid. In the preferred embodiment, the baffle 100 is a urethane foam filter. The liquid is separated from the air by the baffle 100 and drains from the lower side of the baffle to the bottom of the chamber 94 where it passes outwardly of the chamber through a bottom outlet 102. The separated liquid leaving through the outlet 102 is pumped by a pump 104 to the previously mentioned main conduit 82 where it joins with the liquid being pumped by the Moyno pump 78, for delivery to the settling tanks within the tanker vehicle 26.

To reduce the noise of operation, an air silencer 106 is connected to the downstream side of the vacuum pump 84.

To pickup whatever liquid may escape beneath the rear seals 58, a supplemental liquid collection system is provided (FIGS. 5, 6 and 7). The supplemental liquid collection system includes a supplemental housing 110 (FIG. 6) which is carried by the conduit 76 behind the housing 50, extending transversely in parallel relation to the lower end of the wall 54. The housing 110 comprises two enclosed plenum chambers 112 and 114 (FIG. bounded by a transversely extending vertical front wall 116 (FIG. 7) and an upwardly and rearwardly inclined rear wall 118. Depending from the lower extremity of the rear wall 118, is a flexible resilient elastomeric rear seal 120 which depends into sealing relation with the pavement extending rearwardly therealong. Depending from the lower end of the front wall 116 is another flexible seal 122 which has its lower end spaced sufficiently above the pavement to define a narrow gap. The space between the seals 120 and 122 defines an internal, seal chamber 124 communicating with the plenum chambers 112 and 114. At their upper ends, the plenum chambers are connected by ducts 126 which communicate with the interior of the enclosure adjacent its upper end.

In operation, suction applied to the upper interior portion of the enclosure draws liquid entering the seal chamber 124 beneath the seal 122 upwardly through the associated plenum chamber into the enclosure and thence out through the suction port 92. The supplemental collection system thus provides suction pick-up of such liquid as may leak beneath the rear seals 58.

Although the invention has been described with reference to one preferred embodiment, it will be appreciated that many routine changes, modifications and variations may be made in the structure described without departing from the spirit of the invention as set forth in the appended claims hereto.

I claim:

1. A liquid pick-up unit for use with a cutting head assembly for cutting a work surface, the cutting head assembly including a mounting structure, at least one driven rotary cutter rotatably connected to the mounting structure having first and second sides rotating towards, and away from, the work surface, respectively, and a liquid supply member for directing liquid against the first side of the cutter, the liquid pick-up unit comprising:

an enclosure connected to the mounting structure enclosing the cutter, said enclosure having,

an opening facing the work surface through which the cutter projects into engagement with the work surface,

a peripheral seal connected with said enclosure in sorrounding spaced relation to the cutter, said seal extending from said enclosure into sliding, sealing contact with the work surface to substantially reduce escape of liquid from said closure,

an outlet communicating with said enclosure facing towards the second side of the cutter positioned to receive liquid mixed with swarf removed from the work surface by the cutter flung centrifugally from the second side of the cutter towards said outlet;

withdrawal means connected to said enclosure for withdrawing the liquid and swarf therefrom through said outlet; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of the enclosure to assist said seal in preventing liquid within the enclosure from flowing outwardly thereof between said seal and the pavement the application of vac uum through said suction port causing some liquid mixed with air to be withdrawn through said suction port; swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure; recirculation means connected with said swarf separator means for redirecting the separated liquid against the rotary cutter; air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and conduit means connected with said air separator means for delivering the liquid separated thereby to said swarf separator means. 2. A liquid pick-up unit as defined in claim 1 wherein said air separator means comprising:

a generally vertical, closed chamber, an inlet adjacent an upper end of said chamber communicating with said suction port in said enclosure, a vacuum connection adjacent an upper end of said chamber communicating with said vacuum means, a foraminate, substantially liquid-impervious, baffle positioned between said vacuum connection and said inlet to prevent passage of liquid therebetween while permitting the flow of air; and a second outlet adjacent the lower end of said chamber on an opposite side of said baffle from said vacuum connection for outflow of liquid from said chamber, said second outlet communicating with said conduit means. 3. A liquid pick-up unit as defined in claim 2 wherein said baffle is configured as a wall extending entirely across said chamber at a downward inclination.

4. A liquid pick-up unit for use with a cutting head assembly including a mounting structure, at least one driven rotary cutter rotatably connected to the mounting structure having first and second sides rotating towards, and away from, the work surface, respectively, and a liquid supply member for directing liquid against the first side of the cutter, the liquid pick-up unit comprising:

an enclosure connected to the mounting structure enclosing the cutter, said enclosure having, an opening facing the work surface through which the cutter projects into engagement with the work surface, a peripheral'seal connected with said enclosure in surrounding spaced relation to the cutter, said seal extending from said enclosure into sliding, sealing contact with the work surface to substantially reduce escape of liquid from said enclosure; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of the enclosure to assist said seal in preventing liquid within the enclosure from flowing outwardly thereof between said seal and the pavement; a generally horizontal first housing connected to said enclosure extending in parallel relation to the axis of rotation of the cutter spaced from the second side thereof, said housing defining a collecting chamber; a lengthwise first slot in said housing facing towards the cutter positioned to receive liquid mixed with swarf removed from the work surface by the cutter flung centrifugally from the second side of the cutter towards said first slot; at least one pipe communicating with said collecting chamber; a pump connected to said pipe for withdrawing liquid mixed with swarf from said collecting chamber; a second housing connected to said enclosure extending in parallel relation to the cutter spaced from the second side thereof, said second housing defining a second chamber spaced above said collecting chamber; a lengthwise second slot in said second housing facing toward the cutter spaced abovesaid first slot, said second slot constituting said suction port; and means connecting said vacuum means to said second housing for placing said second chamber in communication with said vacuum means. 5. A liquid pick-up unit for use with a grooving head assembly for grooving a pavement, the grooving head assembly including a mounting structure, a horizontal rotary grooving head rotatably connected to the mounting structure for cutting a plurality of parallel grooves in the pavement, the grooving head having first and second sides rotating towards, and away from, the pavement, respectively, and a liquid supply member for directing liquid against the first side of the grooving head, the liquid pick-up unit comprising:

an enclosure connected to the mounting structure enclosing the grooving head, said enclosure having, a downwardly facing opening through which the grooving head projects into cutting engagement with the pavement,

a peripheral seal connected with said enclosure in surrounding, spaced relation to the grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure,

an outlet communicating with said enclosure facing toward the second side of the grooving head positioned to receive liquid mixed with swarf removed from the pavement by the grooving head flung centrifugally from the second side of the grooving head towards said outlet;

withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet;

a suction port communicating with said enclosure;

vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement the application of vacuum through said suction port causing some liquid mixed with air to be withdrawn through said suction port;

swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure; recirculation means connected with said swarf separator means for redirecting the separated liquid against the grooving head; air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and

conduit means connected with said air separator means for delivering the liquid separated there by to said swarf separator means.

6. A liquid pick-up unit as defined in claim 5 wherein said air separator means comprises:

a generally vertical, closed chamber,

an inlet adjacent an upper end of said chamber communicating with said suction port in said enclosure,

a vacuum connection adjacent an upper end of said chamber communicating with said vacuum means,

a foraminate, substantially liquid-impervious, baffle positioned between said vacuum connection and said inlet to prevent passage of liquid therebetween while permitting the flow of air; and

a second outlet adjacent the lower end of said chamber on an opposite side of said baffle from said vacuum connection for outflow of liquid from said chamber, said second outlet communicating with said conduit means.

7. A liquid pick-up unit as defined in claim 6 wherein said baffle is configured as a wall extending entirely across said chamber at a downward inclination.

8. A fluid pick-up unit for use with a grooving head assembly for grooving a pavement, the grooving head assembly including a mounting structure, a horizontal rotary grooving head rotatably connected to the mounting structure for cutting a plurality of parallel grooves in the pavement, the grooving head having first and second sides rotating towards, and away from, the pavement, respectively, anda liquid supply member for directing liquid against the first side of the grooving head, the liquid pick-up unit comprising:

an enclosure connected to the mounting structure enclosing the grooving head, said enclosure having,

a downwardly facing opening through which the grooving head projects into cutting engagement with the pavement,

a peripheral seal connected with said enclosure in surrounding, spaced relation to the grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure;

withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet;

a suction port communicating with said enclosure;

vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement;

a generally horizontal first housing connected to said enclosure extending in parallel relation to the axis of rotation of said grooving head spaced from the second side thereof, said housing defining a collecting chamber;

a lengthwise first slot in said housing facing towards the cutter positioned to receive liquid mixed with swarf removed from the pavement by the grooving head flung centrifugall y from the second side of the grooving head towards said first slot;

at least one pipe communicating with said collecting chamber;

a pump connected to said pipe for withdrawing liquid mixed with swarf from said collecting chamber;

a second housing connected to said enclosure extending in parallel relation to said grooving head spaced from the second side thereof, said second housing defining a second chamber spaced above said collecting chamber;

a lengthwise second slot in said second housing facing toward said grooving head spaced above said first slot, said second slot constitutingsaid suction port; and

means connecting said vacuum means to said second housing for placing said second chamber in communication with said vacuum means.

9. A grooving apparatus for grooving a pavement comprising:

mounting structure;

a horizontal rotary grooving head rotatably connected to said mounting structure for cutting a plurality of parallel grooves in the pavement, said grooving head having first and second sides rotating downwardly towards, and upwardly from, the pavement, respectively;

a liquid supply member for directing liquid against the first side of said grooving head;

an enclosure connected to said mounting structure enclosing said grooving head, said enclosure havmg,

a downwardly facing opening through which said grooving head projects into engagement with the pavement,

a peripheral seal connected with said enclosure in surrounding, spaced relation to said grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure,

an outlet communicating with said enclosure facing towards the second side of said grooving head positioned to receive liquid mixed with swarf removed from the pavement by said grooving head flung centrifugally from the second side of said grooving head towards said outlet;

withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet;

a suction port communicating with said enclosure;

vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement, the application of vacuum through said suction port causing some liquid mixed with air to be withdrawn through said suction port;

swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure;

recirculation means connected with said swarf separator means for redirecting the separated liquid against said grooving head;

air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and

conduit means connected with said air separator means for delivering the liquid separated thereby to said swarf separator means.

10. Equipment for grooving a pavement comprising:

a vehicle movable along the pavement;

at least one horizontal grooving head rotatably connected to said vehicle for rotation about an axis transverse to the direction of motion of said vehicle along the pavement, said grooving head having first and second sides rotating downwardly towards, and upwardly from, the pavement, respectively;

a liquid supply member for directing liquid against the first side of said grooving head;

an enclosure connected to said vehicle enclosing said grooving head, said enclosure having,

a downwardly facing opening through which said grooving head projects into engagement with the pavement,

a peripheral seal connected with said enclosure in surrounding, spaced relation to said grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure,

an outlet communicating with said enclosure facing towards the second side of said grooving head positioned to receive liquid mixed with swarf removed from the pavement, said grooving head flung centrifugally from the second side of said grooving head towards said outlet;

withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet;

a suction port communicating with said enclosure;

vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement, the application of vacuum through said suction port causing some liquid mixed with air to be withdrawn through said suction port;

swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure;

recirculation means connected with said swarf separator means for redirecting the separated liquid against said grooving head;

air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and

conduit means connected with said air separator means for delivering the liquid separated thereby to said swarf separator means.

11. A liquid pick-up unit for use with a grooving head assembly for grooving a pavement, the grooving head assembly including a mounting structure, a horizontal rotary grooving head rotatably connected to the mounting structure for cutting a plurality of parallel grooves in the pavement, the grooving head having first and second sides rotating towards, and away from, the pavement, respectively, and a liquid supply member for directing liquid against the first side of the grooving head, the liquid pick-up unit comprising:

an enclosure connected to the mounting structure enclosing the grooving head, said enclosure having,

a downwardly facing opening through which the grooving head projects into cutting engagement with the pavement,

a peripheral seal connected with said enclosure in surrounding, spaced relation to the grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure,

an outlet communicating with said enclosure facing toward the second side of the grooving head positioned to receive liquid mixed with swarf removed from the pavement by the grooving head flung centrifugally from the second side of the grooving head towards said outlet;

withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet;

a suction port communicating with said enclosure;

vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement;

a first portion of said seal extending generally parallel to said grooving head spaced from the second side thereof;

an intermediate wall parallel to said first portion of said peripheral seal spaced therefrom on the side adjacent said grooving head, said intermediate wall being spaced sufficiently above the pavement to permit liquid to flow into a seal chamber defined by said first portion of said seal and said intermediate wall;

a plenum chamber connected with said enclosure communicating with said seal chamber at the upper end thereof; and

at least one duct connecting said plenum chamber with the interior of said enclosure at a location adjacent said suction port whereby vacuum applied through said suction port draws liquid upwardly from said seal chamber via said plenum chamber and said duct.

12. A method for circulating liquid utilized to cool and flush a pavement grooving head, the grooving head being of the type including a plurality of rotary abrasive cutters engaging a pavement to cut plural grooves therein, the method comprising:

directing the liquid against the grooving cutters on the side thereof moving downwardly towards the pavement, the liquid mixed with swarf abraded from the pavement by the cutters being flung centrifugally from the cutters on the opposite, upwardly moving side thereof;

providing an enclosure around the cutters to confine the liquid within the region of the pavement being grooved by the cutters;

mounting a peripheral seal surrounding the grooving cutters on the enclosure in sliding contact with the pavement to substantially reduce escape of liquid from the enclosure;

applying vacuum to the interior of the enclosure to assist the seal in preventing escape of liquid from the enclosure between the seal and the pavement, the step of applying vacuum to the enclosure causing withdrawal of some liquid mixed with air;

withdrawing liquid mixed with swarf from the enclosure through an outlet positioned to receive the liquid and swarf flung off centrifugally from the cutters;

separating the liquid from the mixed liquid and air;

combining the separated liquid with the liquid mixed with swarf;

separating the liquid from the mixed liquid and swarf;

and

redirecting the separated liquid against the cutters. 

1. A liquid pick-up unit for use with a cutting head assembly for cutting a work surface, the cutting head assembly including a mounting structure, at least one driven rotary cutter rotatably connected to the mounting structure having first and second sides rotating towards, and away from, the work surface, respectively, and a liquid supply member for directing liquid against the first side of the cutter, the liquid pick-up unit comprising: an enclosure connected to the mounting structure enclosing the cutter, said enclosure having, an opening facing the work surface through which the cutter projects into engagement with the work surface, a peripheral seal connected with said enclosure in sorrounding spaced relation to the cutter, said seal extending from said enclosure into sliding, sealing contact with the work surface to substantially reduce escape of liquid from said closure, an outlet communicating with said enclosure facing towards the second side of the cutter positioned to receive liquid mixed with swarf removed from the work surface by the cutter flung centrifugally from the second side of the cutter towards said outlet; withdrawal means connected to said enclosure for withdrawing the liquid and swarf therefrom through said outlet; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of the enclosure to assist said seal in preventing liquid within the enclosure from flowing outwardly thereof between said seal and the pavement the application of vacuum through said suction port causing some liquid mixed with air to be withdrawn through said suction port; swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure; recirculation means connected with said swarf separator means for redirecting the separated liquid against the rotary cutter; air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and conduit means connected with said air separator means for delivering the liquid separated thereby to said swarf separator means.
 2. A liquid pick-up unit as defined in claim 1 wherein said air separator means comprising: a generally vertical, closed chamber, an inlet adjacent an upper end of said chamber communiCating with said suction port in said enclosure, a vacuum connection adjacent an upper end of said chamber communicating with said vacuum means, a foraminate, substantially liquid-impervious, baffle positioned between said vacuum connection and said inlet to prevent passage of liquid therebetween while permitting the flow of air; and a second outlet adjacent the lower end of said chamber on an opposite side of said baffle from said vacuum connection for outflow of liquid from said chamber, said second outlet communicating with said conduit means.
 3. A liquid pick-up unit as defined in claim 2 wherein said baffle is configured as a wall extending entirely across said chamber at a downward inclination.
 4. A liquid pick-up unit for use with a cutting head assembly including a mounting structure, at least one driven rotary cutter rotatably connected to the mounting structure having first and second sides rotating towards, and away from, the work surface, respectively, and a liquid supply member for directing liquid against the first side of the cutter, the liquid pick-up unit comprising: an enclosure connected to the mounting structure enclosing the cutter, said enclosure having, an opening facing the work surface through which the cutter projects into engagement with the work surface, a peripheral seal connected with said enclosure in surrounding spaced relation to the cutter, said seal extending from said enclosure into sliding, sealing contact with the work surface to substantially reduce escape of liquid from said enclosure; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of the enclosure to assist said seal in preventing liquid within the enclosure from flowing outwardly thereof between said seal and the pavement; a generally horizontal first housing connected to said enclosure extending in parallel relation to the axis of rotation of the cutter spaced from the second side thereof, said housing defining a collecting chamber; a lengthwise first slot in said housing facing towards the cutter positioned to receive liquid mixed with swarf removed from the work surface by the cutter flung centrifugally from the second side of the cutter towards said first slot; at least one pipe communicating with said collecting chamber; a pump connected to said pipe for withdrawing liquid mixed with swarf from said collecting chamber; a second housing connected to said enclosure extending in parallel relation to the cutter spaced from the second side thereof, said second housing defining a second chamber spaced above said collecting chamber; a lengthwise second slot in said second housing facing toward the cutter spaced above said first slot, said second slot constituting said suction port; and means connecting said vacuum means to said second housing for placing said second chamber in communication with said vacuum means.
 5. A liquid pick-up unit for use with a grooving head assembly for grooving a pavement, the grooving head assembly including a mounting structure, a horizontal rotary grooving head rotatably connected to the mounting structure for cutting a plurality of parallel grooves in the pavement, the grooving head having first and second sides rotating towards, and away from, the pavement, respectively, and a liquid supply member for directing liquid against the first side of the grooving head, the liquid pick-up unit comprising: an enclosure connected to the mounting structure enclosing the grooving head, said enclosure having, a downwardly facing opening through which the grooving head projects into cutting engagement with the pavement, a peripheral seal connected with said enclosure in surrounding, spaced relation to the grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure, An outlet communicating with said enclosure facing toward the second side of the grooving head positioned to receive liquid mixed with swarf removed from the pavement by the grooving head flung centrifugally from the second side of the grooving head towards said outlet; withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement the application of vacuum through said suction port causing some liquid mixed with air to be withdrawn through said suction port; swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure; recirculation means connected with said swarf separator means for redirecting the separated liquid against the grooving head; air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and conduit means connected with said air separator means for delivering the liquid separated there by to said swarf separator means.
 6. A liquid pick-up unit as defined in claim 5 wherein said air separator means comprises: a generally vertical, closed chamber, an inlet adjacent an upper end of said chamber communicating with said suction port in said enclosure, a vacuum connection adjacent an upper end of said chamber communicating with said vacuum means, a foraminate, substantially liquid-impervious, baffle positioned between said vacuum connection and said inlet to prevent passage of liquid therebetween while permitting the flow of air; and a second outlet adjacent the lower end of said chamber on an opposite side of said baffle from said vacuum connection for outflow of liquid from said chamber, said second outlet communicating with said conduit means.
 7. A liquid pick-up unit as defined in claim 6 wherein said baffle is configured as a wall extending entirely across said chamber at a downward inclination.
 8. A fluid pick-up unit for use with a grooving head assembly for grooving a pavement, the grooving head assembly including a mounting structure, a horizontal rotary grooving head rotatably connected to the mounting structure for cutting a plurality of parallel grooves in the pavement, the grooving head having first and second sides rotating towards, and away from, the pavement, respectively, and a liquid supply member for directing liquid against the first side of the grooving head, the liquid pick-up unit comprising: an enclosure connected to the mounting structure enclosing the grooving head, said enclosure having, a downwardly facing opening through which the grooving head projects into cutting engagement with the pavement, a peripheral seal connected with said enclosure in surrounding, spaced relation to the grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure; withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement; a generally horizontal first housing connected to said enclosure extending in parallel relation to the axis of rotation of said grooving head spaced from the second side thereof, said housing defining a collecting chamber; a lengthwise first slot in sAid housing facing towards the cutter positioned to receive liquid mixed with swarf removed from the pavement by the grooving head flung centrifugally from the second side of the grooving head towards said first slot; at least one pipe communicating with said collecting chamber; a pump connected to said pipe for withdrawing liquid mixed with swarf from said collecting chamber; a second housing connected to said enclosure extending in parallel relation to said grooving head spaced from the second side thereof, said second housing defining a second chamber spaced above said collecting chamber; a lengthwise second slot in said second housing facing toward said grooving head spaced above said first slot, said second slot constituting said suction port; and means connecting said vacuum means to said second housing for placing said second chamber in communication with said vacuum means.
 9. A grooving apparatus for grooving a pavement comprising: mounting structure; a horizontal rotary grooving head rotatably connected to said mounting structure for cutting a plurality of parallel grooves in the pavement, said grooving head having first and second sides rotating downwardly towards, and upwardly from, the pavement, respectively; a liquid supply member for directing liquid against the first side of said grooving head; an enclosure connected to said mounting structure enclosing said grooving head, said enclosure having, a downwardly facing opening through which said grooving head projects into engagement with the pavement, a peripheral seal connected with said enclosure in surrounding, spaced relation to said grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure, an outlet communicating with said enclosure facing towards the second side of said grooving head positioned to receive liquid mixed with swarf removed from the pavement by said grooving head flung centrifugally from the second side of said grooving head towards said outlet; withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement, the application of vacuum through said suction port causing some liquid mixed with air to be withdrawn through said suction port; swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure; recirculation means connected with said swarf separator means for redirecting the separated liquid against said grooving head; air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and conduit means connected with said air separator means for delivering the liquid separated thereby to said swarf separator means.
 10. Equipment for grooving a pavement comprising: a vehicle movable along the pavement; at least one horizontal grooving head rotatably connected to said vehicle for rotation about an axis transverse to the direction of motion of said vehicle along the pavement, said grooving head having first and second sides rotating downwardly towards, and upwardly from, the pavement, respectively; a liquid supply member for directing liquid against the first side of said grooving head; an enclosure connected to said vehicle enclosing said grooving head, said enclosure having, a downwardly facing opening through which said grooving head projects into engagement with the pavement, a peripheral seal connected with saId enclosure in surrounding, spaced relation to said grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure, an outlet communicating with said enclosure facing towards the second side of said grooving head positioned to receive liquid mixed with swarf removed from the pavement, said grooving head flung centrifugally from the second side of said grooving head towards said outlet; withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement, the application of vacuum through said suction port causing some liquid mixed with air to be withdrawn through said suction port; swarf separator means connected to said withdrawal means for separating the liquid from the mixed liquid and swarf withdrawn from said enclosure; recirculation means connected with said swarf separator means for redirecting the separated liquid against said grooving head; air separator means interposed between and communicating with said vacuum means and said suction port for separating the liquid drawn through said suction port from the air mixed with the liquid; and conduit means connected with said air separator means for delivering the liquid separated thereby to said swarf separator means.
 11. A liquid pick-up unit for use with a grooving head assembly for grooving a pavement, the grooving head assembly including a mounting structure, a horizontal rotary grooving head rotatably connected to the mounting structure for cutting a plurality of parallel grooves in the pavement, the grooving head having first and second sides rotating towards, and away from, the pavement, respectively, and a liquid supply member for directing liquid against the first side of the grooving head, the liquid pick-up unit comprising: an enclosure connected to the mounting structure enclosing the grooving head, said enclosure having, a downwardly facing opening through which the grooving head projects into cutting engagement with the pavement, a peripheral seal connected with said enclosure in surrounding, spaced relation to the grooving head, said seal extending from said enclosure into sliding, sealing contact with the pavement to substantially reduce escape of liquid from said enclosure, an outlet communicating with said enclosure facing toward the second side of the grooving head positioned to receive liquid mixed with swarf removed from the pavement by the grooving head flung centrifugally from the second side of the grooving head towards said outlet; withdrawal means connected with said enclosure for withdrawing the liquid and swarf therefrom through said outlet; a suction port communicating with said enclosure; vacuum means connected with said suction port for applying vacuum to the interior of said enclosure to assist said seal in preventing liquid within said enclosure from flowing outwardly thereof between said seal and the pavement; a first portion of said seal extending generally parallel to said grooving head spaced from the second side thereof; an intermediate wall parallel to said first portion of said peripheral seal spaced therefrom on the side adjacent said grooving head, said intermediate wall being spaced sufficiently above the pavement to permit liquid to flow into a seal chamber defined by said first portion of said seal and said intermediate wall; a plenum chamber connected with said enclosure communicating with said seal chamber at the upper end thereof; and at least one duct connecting said plenum chamber with the interior of said enclosure at a location adjacent said suction port Whereby vacuum applied through said suction port draws liquid upwardly from said seal chamber via said plenum chamber and said duct.
 12. A method for circulating liquid utilized to cool and flush a pavement grooving head, the grooving head being of the type including a plurality of rotary abrasive cutters engaging a pavement to cut plural grooves therein, the method comprising: directing the liquid against the grooving cutters on the side thereof moving downwardly towards the pavement, the liquid mixed with swarf abraded from the pavement by the cutters being flung centrifugally from the cutters on the opposite, upwardly moving side thereof; providing an enclosure around the cutters to confine the liquid within the region of the pavement being grooved by the cutters; mounting a peripheral seal surrounding the grooving cutters on the enclosure in sliding contact with the pavement to substantially reduce escape of liquid from the enclosure; applying vacuum to the interior of the enclosure to assist the seal in preventing escape of liquid from the enclosure between the seal and the pavement, the step of applying vacuum to the enclosure causing withdrawal of some liquid mixed with air; withdrawing liquid mixed with swarf from the enclosure through an outlet positioned to receive the liquid and swarf flung off centrifugally from the cutters; separating the liquid from the mixed liquid and air; combining the separated liquid with the liquid mixed with swarf; separating the liquid from the mixed liquid and swarf; and redirecting the separated liquid against the cutters. 